Defining history rules

A history rule identifies properties that change every observation, but that don't indicate an important change, for example a host's sysUpTime property. A history rule allows you to exclude properties from being retained in history, thereby saving resources by not maintaining detailed historical records of changes to these properties.

About this task

A history rule populates the historyExcludeTokens field with field names.

When a resource is updated, the topology service checks if all the updates are on fields that are listed in historyExcludeTokens, and if they are, it updates the resource without creating history.

Procedure

Details

On the Details section of the New history rule (or Edit history rule) page, you define the name, status and tokens for the rule.

  1. Enter a name, which must be unique within the context of the tenant.
    You cannot change the name of an existing rule. If you want a rule to have a different name, create a new rule, then delete the old one.
  2. Toggle the rule status to be either Enabled or Disabled
    Observers will only apply rules which are in an enabled state.
  3. Define tokens for the rule, then click Add+.

    The tokens defined as part of a rule contain the list of shared resource parameter names that will become history exclude tokens for those resources to which the rule is applied. Merge tokens can be constructed using variable substitutions, which allow you to combine more than one property value in a token and also combine them with literal strings.

Conditions

  1. Select observers to which this rule applies from the Observer name drop-down.
    Leave empty to apply the rule to all observers.
  2. Select providers to which this rule applies from the Provider name drop-down.
    Leave empty to apply the rule to all providers.
  3. Select resource types to which this rule applies from the Resource type drop-down.
    Leave empty to apply the rule to all resource types.
  4. Set the Token filter mode to either Exclude or Include, then define a filter in the format of a regular expression. You can set more than one filter.
    Exclude
    Tokens which match any one of the expressions will not be applied to resources.
    Include
    Only tokens which match one of the expressions will be applied to the applicable resources.
  5. Validate you filters using the Validate token filters button.
  6. Click Save.